"We are certainly far better off without velociraptors slashing their way through our cities," he writes. "Our streets are safer with no sabre-toothed tigers. And imagine trying to swat one of those monster prehistoric insects like a vulture-sized dragonfly."

Perhaps more seriously, Shukman also talks about "background" extinction, where species slowly fade out, losing out to others in the endless battle to claim an environmental niche.

The result is that the average species only lasts a few million years. Mammals do worst, surviving between one and two million years. Clams do better at five to seven million.

A few hardy survivors — the leatherback turtle is a prime example of a sturdy design — cling on for tens of millions of years.

But the blunt truth is that the living world is a restless, churning enterprise in which nothing endures forever. Astonishingly, almost every life form that has ever existed on the planet has died out.

It is worth pausing to absorb what that means. Something like 90% - or even 99%, according to some estimates - of every kind of sea creature or land animal or insect or plant that enjoyed a spell on Earth then vanished into oblivion.

Some remains morphed into fossils and ended up on the shelves of museums. Others have left no trace.

Advertisement

Interestingly, Shukman also points out that Charles Darwin was "unsentimental" when it came to extinction. "He certainly did not mourn the passing of the losers," he says.

But Shukman's analysis isn't completely dispassionate. He also argues that the current wave of human-instigated mass extinction should force us to take pause, citing economic and moral reasons. "[A]s the most powerful species on the planet, we have an obligation not to obliterate others, especially if it is through wanton carelessness."